Ian A. York (york at mbcrr.dfci.harvard.edu) wrote:
: I think there are two halves of your question: (1) How do macrophages
: endocytose foreign rather than self antigen:
: differentiation here between self and non-self antigens. There is some,
: however. As well as the opsinizing effects of antibody and complement,
: there seems to be some recognition of different lipids. I can't recall
: the whole story on this, but for example during apoptosis there appears
: to be alterations of the cell membrane, with a loss of the normal
: assymetry of the membrane; the normally hidden lipids act as opsinins and
: enhance phagocytosis. This probably is part of the red cell situation
: you mentioned. I believe there may be other opsinins which are exposed
: or prodced during apoptosis and probably other physiological states.
: Ian
We all know that macrophages do not phagocytose everything that they come
across. If a free-flowing macrophage comes into contact with an antigen it
will pick it up. However it doesn't pick up 'normal' host cells that are
flowing in the blood. This would seem to require a way to differentiate
between the foreign and the self. It may be that there is also ( early in
development) pick up of self antigens but they go through the screening to
be removed just like T and B cells do early in life.
Cheers,
--
Shahram Mori _/\_
Program in Molecular Biology _\ /_
Dept. of chemistry and Biochemistry Box 3C \_ _/
NMSU Las Cruces NM ||
88003